I have been going through the same sort of experience that so many others on this site have been going through including you for the past 4 years. I was also told I had Lyme disease even though I was only positive on one band. I did not have a lot of the symptoms that people with Lyme typically have. I decided to get tested twice more and was negative both times. I wasted a year on various Lyme treatments with no improvement in my condition.
I have also tried adrenal, thyroid, and candida treatments with no help.
Just in the last few days, I got the results of a blood test called a Methylation Pathways Panel. It measures indicators of methylation deficiencies. The main things to look at are glutathione and folate levels. Mine were both very low. This is the first time a blood test has ever shown anything to be deficient in the dozens of tests I have taken.
Anyway, it would be worth getting this panel done. It is expensive ($300) but it may be worth it.
I just started yesterday taking 15mg of methylfolate per day and I am hoping to see a breakthrough soon in my condition.